Download Expressions-Writing

Algebraic Expressions and
Terms
STANDARD : AF 1.2 Write and evaluate an
algebraic expression for a given situation,
using up to three variables.
OBJECTIVE: Students will evaluate expressions by
applying algebraic order of operations and the
commutative, associative, and distributive properties and
justify each step in the process by following and
performing the correct operations, by using math facts
skills, doing critical thinking, writing reflective
summaries, and scoring an 80% proficiency on exit slip
quizzes and online assessments.
Expressions
You are familiar with the following type of
numerical expressions:
12 + 6
3 (12)
6 (3 + 2)
15 - 4 (6)
What is a variable?
In the expression 12 + B, the letter “B” is a
variable.
A variable is a letter or symbol that
represents an unknown value.
Algebraic Expressions
When variables are used with other
numbers, parentheses, or operations, they
create an algebraic expression.
a + 2
(a) (b)
3m + 6n - 6
What are coefficients?
A coefficient is the number multiplied by the
variable in an algebraic expression.
Algebraic Expression
Coefficient
6m + 5
6
8r + 7m + 4
8, 7
14b - 8
14
What is a term?
A term is the name given to a number, a
variable, or a number and a variable
combined by multiplication or division.
Algebraic Expressions
a + 2
3m + 6n - 6
Terms
a, 2
3m, 6n, - 6
What are constants?

A constant is a number that cannot
change its value.
In the expression: 5x + 7y - 2
the constant is - 2.
Figure it out!
Identify the terms, coefficients, and
constants.
1.
2.
3.
4.
12a - 6b + 4
4x - 2y
c - 32
3x + 2
Writing Algebraic Expressions

You can translate word phrases into variable
expressions.
 Examples:
1. Three more than a number = x + 3
2. The quotient of a number and 8 = y/8
3. Six times a number = 6 x n or 6n
4. 15 less than a number = z – 15
5. The quotient of 30 and a number plus 10 =
30/x + 10.
Key words to look for:

Addition:
 Add
 Plus
 Sum
 Total
 Increased by
 More than

Subtraction:
 Minus
 Difference
 Subtract
 Less than
 Decreased by
 less
Cont…

Multiplication
 Product
 Times
 multiply

Division
 Quotient
 divide
EXIT SLIP: Write algebraic
expressions for these word phrases
1.
2.
3.
4.
5.
6.
7.
Four more than s
The product of 7 and c
Nine less than x
A number divided by the sum of 4 and 7.
Twice the sum of a number plus 4.
The sum of ¾ of a number and 7.
Ten times a number increased by 150.
Write an algebraic phrase for these
situations
1.
2.
3.
4.
A car was traveling 35 miles per
hour for a number of hours.
Bob ran 7 times a week for a
number of weeks.
The plumber added an extra $35 to
her bill.
Thirty-five fewer people came than
the number expected.